Our sitting Mayor will be running against himself this year, as the Democratic AND the Republican nominee..
http://www.thepittsburghchannel.com/politics/19692900/detail.html A bit of history on the last go around, where my boss was his challenger.
http://episteme.arstechnica.com/eve/forums/a/tpc/f/34709834/m/892006048831 Wonderful Pittsburgh, where if you're a democrat, then cessation of respiration is not necessarily a disqualification for consideration.