just flat and see a turn. you are in position, and have outs to a boat, which will be the effective nuts, if you are behind. The donk lead is annoying, but we can just flat on 3rd, yes we can get value from aces + spade, 77, some 2 pair combos maybe, but we can also let villain fire worse, and can see his action on next street even if we don't fill up.
Call. Getting 3-bet on the flop is a disaster. The implied odds of our draw, and prospect of usually winning if he checks are enough to call flop + turn. Probably fold river unimproved.