The problem is, the Hungarian sentence is already saying "Hányadik...". So, the question is, how best to translate that into English. But English does not really have a proper equivalent for this question. The closest normal question is "Which ... ". Unless someone has a better idea.
Not bad at all, under the circumstances. :)
What I find fascinating is that there isn't a proper question word for this, when there is a clear need for it.
Imagine you are finishing a race, and the race director says "Congratulations, you are the ####th". You didn't catch the word. What do you do?
I propose: "I'm sorry, I am the how manieth?" :)