Funcinou, faltaram as aspas
create table teste (numero char(5))
insert into teste values (REPLICATE('0',5-Len('1')) + '1')
insert into teste values (REPLICATE('0',5-Len('56')) + '56')
insert into teste values (REPLICATE('0',5-Len('234')) + '234')
insert into teste values (REPLICATE('0',5-Len('4567')) + '4567')
insert into teste values (REPLICATE('0',5-Len('12345')) + '12345')