What term is a hypernym for "story" and "article"?
Solution 1:
Often times, simply the term 'piece' as in 'piece of writing' is used.
i.e.
I mainly do sports journalism, but I also write some fiction. I've had pieces published in The New Yorker, Sports Illustrated, and Esquire.
Solution 2:
If both are contributions to publications, you can use that.