CREATE TABLE table_204_100 (id NUMBER, "date" CLOB, "name of ship" CLOB, "nationality" CLOB, "tonnage" NUMBER, "fate" CLOB)

what is the difference in tonnage between the heaviest and the lightest ships ?
SELECT MAX("tonnage") - MIN("tonnage") FROM table_204_100
SELECT MAX("tonnage") - MIN("tonnage") FROM "table_204_100"