You can leave it up, the hubscore takes a hit but that is all. I have a couple of duplicate articles too.
It would be totally your call, if it is a well written hub I would not worry about it so much. Just make sure you don't have too much duplicate content and you will be fine.
You can delete it, or you can use copyscape and change the parts that are duplicates, it's easy.
But personally I think that you and anyone else here should provide unique content. I have written dozens of articles on the exact same topic and with the same message, but they are always different in nature and the angle of writing, so they are not rewrites. I learn the subject and than I can write about it over and over again without the fear of having a duplicate.
I've had some of these, and when you rewrite the words, then republish it, then they will usually be fixed up. Good luck.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.