CREATE TABLE table_38557 ("Name" TEXT, "Street address" TEXT, "Years as tallest" TEXT, "Height feet / m" TEXT, "Floors" FLOAT)

What's the least amount of floors at 921 sw sixth avenue?
SELECT MIN("Floors") FROM table_38557 WHERE "Street address" = '921 sw sixth avenue'
SELECT MIN("Floors") FROM "table_38557" WHERE "Street address" = '921 sw sixth avenue'