CREATE TABLE table_60490 ("Round" TEXT, "Date" TEXT, "Opponent" TEXT, "Venue" TEXT, "Result" TEXT, "Attendance" FLOAT)

What was the lowest attendance was the opponent was chelsea?
SELECT MIN("Attendance") FROM table_60490 WHERE "Opponent" = 'chelsea'
SELECT MIN("Attendance") FROM "table_60490" WHERE "Opponent" = 'chelsea'