Zoho Creator updates each record submission with the name of the login user who added the record and the time when it was added. Refer the Help topic Display User Name and Time, for more information. The following code added to the on delete -> validate block of the Sript tab, will be executed when a record is deleted. If the added user name is not the same as the login username, the record will not be deleted. 

on  delete
    {
        on validate
        {
            if (input.Added_User  !=  zoho.loginuser)
            {
                alert "You can delete only your records";
                cancel delete;
            }
        }
    }