>SELECT NUMBER FROM TEST WHERE AMOUNT>=(SELECT MAX(AMOUNT) FROM
>TEST WHERE AMOUNT<(SELECT MAX(AMOUNT) FROM TEST))

Well, I suppose you can do it this way if you've only got four records in
your table, but this kind of query may be very slow if there is a
substantial number of records in the table. For Firebird, the preferred
method would be SELECT FIRST 2 as someone said. If you're running some
older Interbase version, using EXISTS is also quite quick:

SELECT NUMBER FROM TEST T1
WHERE NOT EXISTS(
SELECT 1 FROM TEST T2 WHERE T2.AMOUNT > T1.AMOUNT AND EXISTS(
SELECT 1 FROM TEST T3 WHERE T3.AMOUNT > T2.AMOUNT))

Set