CREATE TABLE table_64723 ("Date" CLOB, "Tournament" CLOB, "Surface" CLOB, "Opponent" CLOB, "Score" CLOB)

What was the date of the tournament with a clay surface and an opponent of Irina Falconi?
SELECT "Date" FROM table_64723 WHERE "Surface" = 'clay' AND "Opponent" = 'irina falconi'
SELECT "Date" FROM "table_64723" WHERE "Opponent" = 'irina falconi' AND "Surface" = 'clay'