[__cadetill]

no lo he probado, pero pueba a investigar por aquí:

Código SQL [-]

select substring(cast(Num_Exp as varchar(7)) from 1 for 4) as Ano,
      substring(cast(Num_Exp as varchar(7)) from 5 for 7) as Increm
from tabla
order by 1, 2

Espero te sirva