Mark Murphy, a former aide to the New York City public advocate, announced a bid for Congress on Wednesday in the Empire State’s 13th district.

Murphy, son of former Rep. John Murphy (D-N.Y.), is currently the only declared candidate in the Democratic race. If he wins the nomination, as many Democrats expect, he’ll face freshman Rep. Michael Grimm (R) in November in what is likely to be one of New York’s more competitive districts.

Grimm beat Democratic Rep. Mike McMahon in 2010 with 51 percent of the vote. Redistricting remains a question mark in New York, but the 13th is likely to continue to be anchored in Staten Island.

In a telephone interview with Roll Call on Thursday, Murphy ticked through national Democratic talking points but seemed unsure of what, exactly, he believed. He said he was going to campaign hard against a “say-no Congress.” But Murphy became flustered and had trouble coming up with an answer when asked what, in particular, he opposed that Congress had said no to.

Still, in a strongly anti-Washington cycle, being an unpolished non-politico is unlikely to be a fatal flaw.

Later, Murphy said he was irked that Congress had said “no to extending unemployment benefits to folks who had lost their jobs in this downturn” and no to “protecting Medicare.”

Grimm ended December with more than $1 million in cash on hand, but Democrats expect Murphy to be competitive.

“His knowledge of Staten Island is tremendous, and he comes at this from a local perspective,” said one New York Democrat with knowledge of the district.

The Democratic Congressional Campaign Committee said Murphy is a “strong candidate with real fundraising potential.”

Murphy said he would “be very competitive in raising the amount of money needed to win this.” He added he would be willing to “make an investment of my own,” that is, partially self-fund. Murphy wouldn’t say how much he might put in.

“Congressman Grimm is not concerned with every liberal Democrat who throws his hat into the ring,” Grimm spokesman Carol Danko said in a statement. “He remains concerned with doing what’s best for the people he represents in Staten Island and Brooklyn, whether it be fighting for jobs, strengthening the economy or overturning the Port Authority’s outrageous toll hikes.”