I know what is anime and manga, but could I ask about Korean dramas here? Or maybe should I ask this topic on Movies & TV Stack Exchange instead?
Questions regarding Korean dramas would not be on topic here. You can read more about what is on topic in our help center.
However you can take a look over at Movies.SE Judging by their what is on topic list, I would assume that questions about Korean dramas are on topic. As long as the question suffices to their standards.