Appears like both TOP & LIMIT are not supported.
You can try using the RANK or ROW_NUMBER option shown in the SAP Note 1885029.
Something like,
select
field1,
field2,
(select PROFIT_CTR (select PROFIT_CTR, rank() over (order by COMP_CODE) rnk from "MySchema"."MyTable" where COMP_CODE = '1234') WHERE rnk <= 1 as PC)
from "MySchema"."OtherTable" where....
etc
Thanks,