I asked a duplicate question and the community flagged it as duplicate. So I accepted it as duplicate. Now what? Am I supposed to delete it? I ask this because even after accepting that it is a duplicate, people are down voting.
Well, if they are really duplicates and they have no answer, they are probably not of that much value to the community. Hence you could delete them. Note that duplicates has a significant value in finding the duplicate question. Your question might contain keywords the original doesn't have, so keep them if you wish.
I should warn you though that asking multiple duplicate questions may lead to a question ban (deleting posts do count toward a question ban too). The problem with those questions is: there usually isn't much to improve so they get reopened which may get you out of a ban.
So instead of worrying whether you should delete them or not, worry about asking questions that are a duplicate. That is much worse than actually deleting them.