Sometimes leaving your clan is the hardest decision.
If there are no Clan members left when you leave your Clan, the Clan will be deleted.
Otherwise, the new Clan Owner will be the official with oldest account creation date. If there are no officials, then the same rule will apply to members.
Keep in mind that if you ever leave your clan, our Zookeepers team won't be able to interfere in its hierarchy. This means that it will be impossible for us to change the clan leadership to a chosen person or to return it to a previous leader.
That said, a nice tip is: you can always make sure this goes to a specific person if he's the only official in the clan.
Hope you can take the best decision for your team!