Depending on the order of the columns in your table you can use VLOOKUP or INDEX/MATCH.

The Index/Match will work no matter the order, so safer to use that.

e.g.

=INDEX($B$2:$B$100,MATCH(X2,$A$2:$A$100,0))

where A2:A100 contain the Zip codes and column B has the Cities, X1 contains the Zip code to look up.