"I think it's a good thing to say, 'I'm willing to take a tough vote, even if it means I'm going to lose my seat,' " Margolies said.
Margolies, a former television reporter who teaches at Penn's Fels Institute of Government, is keeping at least one campaign strength under wraps for now.
Her son, Marc Mezvinsky, in 2010 married Chelsea Clinton, daughter of the former president and former U.S. Secretary of State Hillary Rodham Clinton.
Margolies said "we haven't tested the waters" on having the powerful Clinton family fundraise for her 2014 Democratic primary election. But that potential support makes Margolies a quick front-runner in the race.
"I want very badly to run on my own record," she said. "I think I'm being careful with that because they are family."
Margolies lives in Wynnewood, part of U.S. Rep. Chaka Fattah's district, but is looking for a home in the 13th District, which covers eastern Montgomery County and part of Northeast Philadelphia.
The other Democrats in the race are state Rep. Brendan Boyle of Northeast Philly; state Sen. Daylin Leach of Montgomery County; and Dr. Valerie Arkoosh, a professor at the University of Pennsylvania School of Medicine. State Rep. Mark Cohen of Philadelphia and former City Controller Jonathan Saidel briefly filed to run, but have withdrawn.
The GOP in the 13th
The 13th District seat is open next year because U.S. Rep. Allyson Schwartz entered the 2014 Democratic primary election for governor. While several Democrats are eager to replace Schwartz, Republicans are moving at a more cautious pace.
Margolies may have something to do with that.
Marina Kats, an attorney from Abington, lost a bid for the 13th District to Schwartz by 28 points in 2008. Kats is "seriously considering" another run but sees Margolies as a front-runner due to her anticipated support.
Carson "Dee" Adcock lost to Schwartz by nearly 13 points in 2010. He hasn't ruled out another run, but thinks it will be a "formidable task" for a Republican to win.
Adcock, who lives in Abington and runs his family's plumbing supply business, cites three reasons for concern: Clinton support for Margolies, the district trending Democratic and the 2011 redrawing of the district lines - by Republicans in Harrisburg - that made it more hospitable to Democratic candidates.
Republican officials in Philadelphia and Montgomery County said attorney Joshua Quinter, who lost the 2010 GOP primary to Adcock, and retired U.S. Air Force Col. Beverly Plosa-Bowser are also interested in the race.
" Actually, I had dated her roommate before. Her roommate canceled a date because she had cut her foot or something. So I said, would you mind if I take Sue to the movie? That was it." - Gov. Corbett, in a new "Out & About" video on Philly.com, explaining how he met his wife in college.
On Twitter: @ChrisBrennanDN