Is it advised to delete the question? Or should I just leave it alone?
You should leave it alone.
Many places contain the answers to people's questions. Stack Exchange tries to be the place where people can efficiently find the answers they need, and this is a much harder problem to solve.
We assume that, when you posted a question
- You searched on the site to see if it has been asked before and found nothing of interest.
- You clicked "Ask question" and typed in a title. The system immediately showed you questions it thinks are related.
- You typed a text and posted. The system linked related questions in the sidebar.
If you did not notice a duplicate at any of the steps - either because the system did not find it or because the titles didn't seem related to you - then you think about your question using different wording than the people who asked and answered the old one. And the difference is so large the system can't recognize it. So, what happens if somebody with your way of thinking has the same question? If yours is deleted, he finds nothing and either posts again (another dupe to deal with) or goes away disappointed. If yours exists, he finds it, and follows through to the dupe target.
Even if you failed to notice the dupe target not due to system failure but because of your own tunnel vision, there is still a nonnegative chance that the dupe will help somebody else with a wording similar to yours but too different from the original one. So, again, keep the dupe.
If both questions have very good but different answers, such that it would be useful for everybody interested to read both (not an "either is sufficient" case), you should flag for a moderator to merge.
This question gives space to another scenario the currently accepted answer isn't considering.
What if my question was marked as duplicate and I disagree with it?
In this specific case, I suggest you to write a comment or edit the question explaining what is different from your question and the other one and then vote to reopen.
As a reviewer of Reopen votes, I like in particular when users edit the question, but the writing a comment is also fine, specially when that's the only comment the question has.
You have posted a question and the post has been closed as a duplicate.
If you are not satisfied with given answer(s) on duplicate post, then you should edit your post to make difference and you can add "Please, this question is not duplicate"; give your valid reason why this post is not a duplicate.
If you are satisfied with given answer(s) on duplicate post. You should not delete the post otherwise, deletion of post counts against you and you may got suspension to ask more queries. Try to edit post to make better quality of your post and don't delete your post.