This is a library that helps map census demographics (or really any census data) mappable to geographies specific to Philadelphia using geojson files available from Open Data Philly.
An explanatory notebook is here to explain the ways that demographic data gets mapped to Police Service Areas.
You can also run generate_csvs.py to re-generate the CSVs.
If you just want the demographics by PSA, you can download by census block group centroid.