Gibson Armstrong

Even with no incumbent, and even at a time when the state's electoral demographics are in flux, some legislative seats stubbornly stay in the hands of one party.

Take, for example, Pennsylvania's 13th and 17th Senatorial Districts. One Republican-held, one Democrat-held, neither seems poised for a party-change, pollsters and analysts say.

In the 17th, a seat being vacated by Sen. Gibson Armstrong (R-Lancaster) is being sought by Democrat Jose Urdaneta and Republican Lloyd Smucker. In the 13th, it's Republican Lance Rogers and state Rep. Daylin Leach (D-Montgomery) vying to replace departing Sen. Connie Williams, the district's Democratic senator since 2001.