If the two docs have the same name they must have been saved in different folders, unless what you are selecting is a short cut to one unique doc.

If in fact there are two docs with exactly the same name they cannot possibly have been saved in the same folder.  So, find the folders where they are saved and rename one of the docs.

Then you will be able to open them both at the same time for comparison, and then either keep one as a back-up or delete it if you don't want to keep it.

If it was me, I would keep a back-up anyway.