It’s the same old Tsong, but a different theme since Paul’s been gone.

The late Senator’s wife Niki Tsongas (D) is scheduled to take over her the House seat her husband once held in a swearing-in ceremony this morning, following her special election victory in Massachusetts’ 5th district Tuesday. Tsongas defeated Republican Jim Ogonowski by 6 points with 51 percent of the vote in the special contest that brought 105,985 people to the polls.

The 5th district is considered the most conservative district in the very blue Bay State. Former Gov. Mitt Romney (R) won the district when he carried the state in 2002 and sitting Democratic Gov. Deval Patrick won the district with 50 percent, though he carried the state with almost 56 percent.

The National Republican Congressional Committee hailed the closer-than-expected election in Massachusetts as a sign that the “Democratic wave breaks” and that the right GOP campaign can be competitive in even the bluest of districts.

“The Ogonowski campaign is a pretty good reminder that you can go a long way without a lot of money,” NRCC Chairman Tom Cole (Okla.) said during a briefing with reporters on Wednesday.

Tsongas, who outspent Ogonowski by about 4-1, defeated the Republican to become the first female in her state’s Congressional delegation in more than 25 years.

“A 6-point margin is not exactly what you call close,” said Democratic Congressional Campaign Committee spokeswoman Carrie James. “I think her campaign exceeded expectations.”

Tsongas emerged from a very competitive multicandidate primary in September. Many national figures, including Speaker Nancy Pelosi (D-Calif.) and former President Bill Clinton hit the trail for her during the six-week period leading up to the general election.

“Over the seven months since announcing my intention to run in March, I’ve traveled thousands of miles throughout the 29 cities and towns of this district,” Tsongas said in her prepared victory remarks. “To all of these people — and the countless others like them — my message is simple. Let’s get to work.”

For Tsongas, work starts tomorrow with her plan to vote to override President Bush’s veto on the State Children’s Health Insurance Program. She’s also said on the stump that her preference is to work on the Education and Labor or Armed Services committees, where her predecessor, former Rep. Marty Meehan (D-Mass.), served before he resigned from Congress in July.

“Less than 48 hours from now, I will have the honor of going to Washington and casting my vote to override the president’s veto of legislation that would expand health care coverage to 10 million kids,” Tsongas told supporters on Tuesday night. “There is no better way that I can think to start my service in Washington as the first woman elected to Congress from Massachusetts in 25 years.”

According to her campaign aides, Tsongas has been calling on her husband’s former colleagues for advice, including Rep. Barney Frank (D-Mass.), who endorsed her before the primary.

The daughter of an Air Force engineer who lived all over the world, Tsongas settled in Lowell, Mass., after marrying. Before her Congressional bid, Tsongas was a dean at a local community college.

She and her late husband, Paul Tsongas, who spent a term in the Senate after serving in the House and ran for the Democratic presidential nomination in 1992, have three daughters.

Tsongas was asked at her victory party Tuesday night about what her husband would think about her win.

“I think he would have been very happy for this for lots of reasons,” she replied. “But also because as a father of three daughters, it’s important to have diversity in the delegation.”