CREATE TABLE table_57128 ("Year" FLOAT, "Men's singles" CLOB, "Women's singles" CLOB, "Men's doubles" CLOB, "Women's doubles" CLOB, "Mixed doubles" CLOB)

Which mixed doubles was featured in 2006?
SELECT "Mixed doubles" FROM table_57128 WHERE "Year" = '2006'
SELECT "Mixed doubles" FROM "table_57128" WHERE "Year" = '2006'