Complex sentence: Each of the 50 areas is represented on the City council by one Alderman and in many social, political and economic contexts, it is reasonable to describe what part of Chicago one is from by who one's alderman is or what ward one lives in.
Split into simpler sentences: Each of the 50 areas is represented on the City council by one Alderman. In many social, political and economic contexts, it is reasonable to describe one's residence in Chicago by who one's alderman is or what ward one lives in.