There are two Maple processes you have to consider - 'automatic simplification' and 'evaluation'. It is relatively easy to suspend the latter using unevalution quotes, as in
a:=''2*x-5''>''3*x-6''; not a double quote but two forward single quotes
which will return
a := '3*x-6' < '2*x-5'
Notice however that if one subsequently enters 'a' in your worksheet, then 'a' will be 'evaluated' again, and 3*x<2*x-1 will be returned
Notice also that this approach does not prevent automatic simplification. Contrast the above with
The 'automatic simplification' process will 'simplify' the 6+1 part on the rhs, but the expression is otherwise unevaluated so this one returns
a := '3*x-5' < '2*x-5'
If you want to avoid both automatic simplification and evalutation then you best bet is probably the InertForm package.
a:=InertForm:-MakeInert(2*x-5) > InertForm:-MakeInert(3*x-6+1); #Note the 6+1 which will be 'simplified'
will return an inert form which (unlike evaluation quotes) will remain inert in subsequent evaluations, until/unless one uses the command
If you really, really want to kill the automatic simplification process as well, you can use the construct
use InertForm:-NoSimpl in 2*x-5>3*x-6+1; end;