For those in the Jewish religion. If I became a jew which of the 12 tribes would I belong to?

Answer 1

Converting to Judaism does not make you Jewish by ethnicity, so while you (as a hypothetical convert) are considered Jewish by any mean you cannot claim to be of a certain tribe.

But if you marry into the Jewish faith and bring up Jewish children, they are considered of the tribes of Judah and Benjamin, as these two tribes, alongside with the Levis who lived among them, are the only certain tribes that were remained after the Diaspora.
The modern people of Israel (Jews) are descents of Judah, Benjamin and Levi but it is impossible for us to track our ancestry back to the times of the tribes and define which is which (although any person who bears the surname "Levi" is most certainly a descent of the Levis).

Answer 2

Anyone who does not have a clear heritage linking back to a tribe goes under the tribe of Judah....which means Jews

Answer 3

You would be one of the 12 tribes, yes indeed. You'd be grafted into the nations. As to which tribe, you can contact me and I'll help you out with that. :D
~jAEL

Answer 4

you would have no tribal affiliation.