Okay -- you have ID or Unique ID which will be the row in Project like 1, 2, 3, 4, etc. Not sure why I remembered the 1.1 (probably convention we always use so stuck in my mind) but you have the Outline Level which will indicate top level (1) or second level (2) or ...
Oh wait, that just reminded me. That is where the 1.1 is, look also at the Outline Number column.
Hope that helps.