Indiana Rep. Joe Donnelly’s unlikely victory on Nov. 2 stands in stark contrast to what happened in the rest of the country and the rest of the Hoosier State, and a new memo from Donnelly’s campaign spells out exactly how lucky he was.

The northern Indiana Democrat defeated Republican state Rep. Jackie Walorski, 48 percent to 47 percent, according to the Indiana Secretary of State’s unofficial election results. Yet Republicans swept statewide offices in Indiana, while its Senate seat and two House seats switched from Democratic to Republican hands.

And according to analysis from the Sunlight Foundation included in the Donnelly memo, the Congressman was the 12th-most-targeted Democratic Congressman by outside groups.

The National Republican Congressional Committee showed winning Donnelly’s seat was a priority when it targeted him with its first independent expenditure ad in September. But other groups were not far behind: the 60 Plus Association, American Action Network, Crossroads GPS, Susan B. Anthony List, American Crossroads, and New Prosperity Foundation each spent more than $100,000 to defeat Donnelly.

Of the 11 Democrats targeted with more third-party spending than Donnelly was, only five won re-election: Reps. Mark Critz of Pennsylvania, Gary Peters of Michigan, Martin Heinrich of New Mexico, Bruce Braley of Iowa and Ed Perlmutter of Colorado. South Dakota Rep. Stephanie Herseth Sandlin and Alabama Rep. Bobby Bright, the Democrats who were 13th and 14th on the list, respectively, also lost.

The memo also noted that Donnelly was one of the few Democrats in Republican-leaning districts to win re-election. His district is likely to become more Republican following redistricting, though, so Donnelly may look at running statewide instead of running for re-election in 2012. Sen. Dick Lugar (R) is up for re-election, and term limits won’t allow Republican Gov. Mitch Daniels to run for re-election in 2012.

Donnelly, an attorney and small-business owner, was first elected to Congress in 2006, defeating Rep. Chris Chocola, the Republican who now leads the Club for Growth. Donnelly is a member of the fiscally conservative Blue Dog Coalition.