CREATE TABLE table_72978 ("Aircraft" TEXT, "1990" FLOAT, "destroyed" FLOAT, "damaged" FLOAT, "to Iran" FLOAT, "survived" FLOAT)

If the aircraft was ussr mig-25 rb how many were destroyed?
SELECT "destroyed" FROM table_72978 WHERE "Aircraft" = 'USSR MiG-25 RB'
SELECT "destroyed" FROM "table_72978" WHERE "Aircraft" = 'USSR MiG-25 RB'