The one here, not that (4)
I believe the answer is:
this
I believe this clue is a double definition.
'the one here' is the first definition.
(I've seen this in another clue)
'not that' is the second definition.
(this one as opposed to that one)
(Other definitions for this that I've seen before include "near thing" , "The thing here referred to" , "The thing under discussion" , "The thing just mentioned" , "Pronoun to point out nearby things" .)