Following news reports is essential to getting a grip on how local politics works.
There are two databases that cover newspapers.
Pew Philadelphia Research Inititiative State of the City Annual Reports "research highlights the essential facts about Philadelphia, its residents, neighborhoods, and major issues. From demographics, to culture and government, to residents’ opinions, “State of the City” is a data-dashboard for the benefit of both the public and leaders who are driving the city’s future."
The Committee of Seventy is an important local watchdog group focusing on elections and reform.
Encyclopedia of Philadelphia connects the past and the present
CQ Researcher Online is a publication that does excellent balanced reports on all kinds of topics particularly of interest to policymaking-- with lots of help in suggesting other sources. It's both a good source for looking for ideas and looking to see if they have covered a topic you have in mind. The perspective is national and international.
A search on the phrase Philadelphia and politic* in the database Academic Search Complete gives rather wide results from academic journals, magazines, and newspapers. This gives you a sense of what news from Philadelphia is significant to the national press. (Some of these results are from articles from scholars based in Philadelphia.on completely unrelated topics.) You can narrow your search with more terms or look at specific publicatio formats. Again, magazines and newspapers are usually the most readable. Ethnic Newswatch gives another perspective on Philadelphia and politic* as does the database GenderWatch for Philadelphia and politic*.