The exact text of what Martin Niemoller said, and which appears in the _Congressional Record_ 14, October 1968, page 31636 is:

When Hitler attacked the Jews I was not a Jew, therefore I was not concerned. And when Hitler attacked the Catholics, I was not a Catholic, and therefore, I was not concerned. And when Hitler attacked the unions and the industrialists, I was not a member of the unions and I was not concerned. Then Hitler attacked me and the Protestant church -- and there was nobody left to be concerned.

-Harry W. Mazal in San Antonio, Texas

Reprinted for your reference by Angus B. Grieve-Smith.