Just delegate 0 SPT to the same account and the undelegating should start. But be aware that this process takes 7 days, so you can delegate your SPT to the real Monter Curator account in a week.
PS: I don't know if you will get anything in return for your 113 SPT delegation, I guess you would have to delegate more to get return. But not sure, you can try.
RE: How to undelegate if you typed the wrong account?