Hi, If you don't care who owns the Feature but want to find any Feature with a child story you own, I believe this would also work. For a list of Features using Custom List app on a dashboard, in the Query box on Settings page:
(UserStories.Owner.DisplayName = "JohnC"). DisplayName will match what you see when you have the Owner field displayed on a list or board. If you omit that, Owner will match the UserName (or login name).
(UserStories.Owner = "john.curent_user@acme.com")