CREATE TABLE table_55448 ("Date" CLOB, "Tournament" CLOB, "Winning score" CLOB, "To par" CLOB, "Margin of victory" CLOB, "Runner ( s ) -up" CLOB)

When was the Masters Tournament?
SELECT "Date" FROM table_55448 WHERE "Tournament" = 'masters tournament'
SELECT "Date" FROM "table_55448" WHERE "Tournament" = 'masters tournament'