I'm sorry to say that when I got your application I'd just appointed someone to lead potions!

Now, you have choices, I've just received an application for Dueling, and the only other club free is Art. You're welcome to that, however if you'd rather not have that you could ask the person who has just got potions if they'd like a co-leader, or you can, um, wait and see if someone takes Art at which point clubs starts accepting ideas for new clubs :)