I had a question get closed as a duplicate. Should I delete it? Should I accept the one answer someone gave for the question? I'm not really sure how to handle these.
You don't need to delete it, and you don't need to accept the answer. Don't worry much about it.
A moderator (or community voting) may eventually delete a closed question, but questions closed as duplicates are often left as-is because they provide alternate question titles useful for others who are searching for an answer to a similar question. (Google will index all of the versions.)
i.e. The differently-worded duplicate serves as an alternate way to find the original question.