From your post you never actually enrolled in any classes at the 2nd school, right? you never went there, you never had any experience of it-you were accepted as a transfer student and took a leave of absence before enrolling, yes? If so you didn’t actually ever ‘go’ there. Yes, if/when you apply to a new school you put that you are on a LOA from school #2 (and you withdraw from school #2!).
Unless…the situation is murkier than you are saying here…