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