CREATE TABLE table_56926 ("Rank" FLOAT, "Nation" CLOB, "Gold" FLOAT, "Silver" FLOAT, "Bronze" FLOAT, "Total" FLOAT)

what is the highest amount of silver when gold is 0 for soviet union?
SELECT MAX("Silver") FROM table_56926 WHERE "Gold" = '0' AND "Nation" = 'soviet union'
SELECT MAX("Silver") FROM "table_56926" WHERE "Gold" = '0' AND "Nation" = 'soviet union'