I was corrected on a phrase I misheard in this question and it was subsequently put on hold as the correction only pertains to me. I would like to know what the protocol is in this case - should I delete it?
If you think it won't help anyone in the future, you can delete it. Otherwise, keep it.
The idea behind closing these questions is explained in our meta discussion about typo questions. Here's what Szymon wrote:
Questions of that kind are unlikely to help anyone but the asker and that is a reason enough for closing, in my opinion.
The idea behind Stack Exchange, including our own site about the Japanese Language, is to create a library of knowledge for future users to find and use as a reference. What we'd like is for people to search on Google and find useful information on our site.
We're glad that we could help you by pointing out the typo in the comments section, but we don't need to keep the question around unless you feel your question makes a significant contribution to that library. Will future users find it useful? If you think they might, then feel free to leave it on the site. (It'll be saved from automatic deletion if users upvote it.) But if you think that you're the only one who's likely to benefit, feel free to delete the question.