CREATE TABLE table_56819 ("Outcome" TEXT, "Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Opponent in the final" TEXT, "Score in the final" TEXT)

Which date has an Outcome of runner-up, and an Opponent in the final of gilles simon?
SELECT "Date" FROM table_56819 WHERE "Outcome" = 'runner-up' AND "Opponent in the final" = 'gilles simon'
SELECT "Date" FROM "table_56819" WHERE "Opponent in the final" = 'gilles simon' AND "Outcome" = 'runner-up'