The Bundestag constituency of Cologne IV was a constituency in North Rhine-Westphalia from 1965 to 2002 . Most recently it included the districts of Kalk and Mülheim in the independent city of Cologne. Since its dissolution, the Kalk district has been part of the Cologne I constituency and the Mülheim district has been part of the Leverkusen - Cologne IV constituency . The constituency was always won by candidates from the SPD , most recently by Günter Oesinghaus .