What about (West) Berlin before 1990?
West Berlin was not allowed to vote in federal elections before unification. It was the D.C. of West Germany.
More like Puerto Rico. 
DC wasn't even allowed to vote for President until the 1960s
I was rather referring to West Berlin/Puerto Rico's status as a remote, autonomous exclave that hasn't acquired full statehood, with its inhabitants holding citizenship but not (national) voting rights.
That's where the parallels end though, since Puerto Rico is indeed a formal part of the United States. West Berlin on the other hand was merely treated as a de facto part of the Federal Republic of (West) Germany, while it officially remained an Allied-occupied territory until 1990 (a status that had already ended for West Germany in 1955 with the Bonn-Paris conventions taking effect).
