select 
    CLASS,
    PERSON,
    HOUSEHOLDS
from(
    select *,row_number() over(partition by CLASS order by HOUSEHOLDS desc) num 
        from (
        select
         CLASS_NAME CLASS
        ,PERSON_NAME PERSON
        ,sum(AMT) HOUSEHOLDS
        ,CLASS_CODE
        from
            HOUSEHOLD
        where
            PERSON_CODE != '1' and CLASS_CODE != '01'
        group by 1,2,4
        )
    )
where num =1
order by CLASS_CODE