CREATE TABLE table_57375 ("Date" TEXT, "Opponent" TEXT, "Score" TEXT, "Loss" TEXT, "Attendance" FLOAT, "Record" TEXT)

What is the average attendance against the expos?
SELECT AVG("Attendance") FROM table_57375 WHERE "Opponent" = 'expos'
SELECT AVG("Attendance") FROM "table_57375" WHERE "Opponent" = 'expos'