CREATE TABLE table_12991 ("Nat." TEXT, "Name" TEXT, "Moving from" TEXT, "Type" TEXT, "Transfer window" TEXT, "Ends" TEXT)

What is the transfer window for the moving from of S o Paulo?
SELECT "Transfer window" FROM table_12991 WHERE "Moving from" = 'são paulo'
SELECT "Transfer window" FROM "table_12991" WHERE "Moving from" = 'são paulo'