Filter based on track number

I am struggling to filter based on track number. For a media center I need to have leading zeroes in front of tracks 1 to 9 in order for a proper view.

I tried a few things but they don't work. I am obviously missing someting simple, any help appreciated. Some files already have leading zeroes or even two for some compilations.

track is 1 (displays lots of files)
%track% is 1 (displays nothing)
%_track% is 1 (displays nothing)
and all of these with "is" replaced for "matches" and 1 in brackets "1

track matches 1
track matches "1"

Also tried TRACK and Track but afraid I am missing someting simple

Please note that the operation keywords have to be in capitals.
so it should be
track IS 1
To filter all tracks where you have no leading zero, you could try
NOT track HAS 0 AND %track% MATCHES ^\d$

Thanks! Feel like a fool now, appreciate the help!