CREATE TABLE table_31476 ("Round" FLOAT, "Circuit" TEXT, "Date" TEXT, "Length" TEXT, "Pole Position" TEXT, "GT3 Winner" TEXT, "GT4 Winner" TEXT)

When david ashburn richard westbrook is the gt3 winner and 1 is the round what is the length?
SELECT "Length" FROM table_31476 WHERE "Round" = '1' AND "GT3 Winner" = 'David Ashburn Richard Westbrook'
SELECT "Length" FROM "table_31476" WHERE "GT3 Winner" = 'David Ashburn Richard Westbrook' AND "Round" = '1'