Did Obama really win NY-11 in 2012? I thought that was a Safe R district and was treated as such even in the 2015 special election?
Yeah. Obama won it by 5, IIRC. He won Staten Island by a few points and the Brooklyn portion by more (it's quite significantly to the left of Staten Island). It's probably largely a result of Hurricane Sandy "rally around the President" more than ideological support for him, though. Look at the other districts in the NYC metro where Obama did significantly better than Clinton. NYC is basically one of the only major metros in the country that swung to Trump.
How did Trump do in the Brooklyn part of NY-11? I thought it was considered a decent political match to Staten Island?