You own the copyright. Unless of course you explicitly transferred it to the college newspaper, but then you would know.
This is a good example why a registration based system is bad: as a student you would likely not have bothered registering for copyright on your humor column, while in the present system you enjoy the protections and can republish as you like.
(If you had worked for a commercial newspaper, you would have created a work for hire and the newspaper would detain the copyright. I'm not sure what happens to copyright when the newspaper disappears but this is unrelated to copyright registration)
This is a good example why a registration based system is bad: as a student you would likely not have bothered registering for copyright on your humor column, while in the present system you enjoy the protections and can republish as you like.
(If you had worked for a commercial newspaper, you would have created a work for hire and the newspaper would detain the copyright. I'm not sure what happens to copyright when the newspaper disappears but this is unrelated to copyright registration)