Philly has changed a lot over the years. And some boundaries continue to change.
Following the 2010 Federal Census, boundaries were redrawn for congressional, state Senate and House, and City Council districts. (Council had to get the job done within six months or lose their salaries. Why isn't that the case more often?)
Bear in mind that new state Senate and House districts do not technically go into effect until after the 2014 elections. City Council's redrawn lines aren't official until 2016. However, Council passed an ordinance in 2013 allowing members to serve constituents within the new boundaries.
To find your district and who represents you, use Azavea's Elected Officials and Districts tool.