This way
--Dummy table
DECLARE @ModalNumbers TABLE
(
ModalNumber VARCHAR(50)
)
INSERT INTO @ModalNumbers
select 'asdf 023k-a'
union all
select 'asdf 023k-b'
union all
select 'asdf 023k-c'
DECLARE @SearchTerm VARCHAR(15)
SET @SearchTerm = 'asdf023ka'
select * from @ModalNumbers
where REPLACE(REPLACE(ModalNumber,'-',''), ' ', '') = @SearchTerm OR ModalNumber = @SearchTerm
SET @SearchTerm = 'asdf 023k-c'
select * from @ModalNumbers
where REPLACE(REPLACE(ModalNumber,'-',''), ' ', '') = @SearchTerm OR ModalNumber = @SearchTerm