CREATE TABLE table_23456 ("Number" FLOAT, "Registration" TEXT, "First flew" TEXT, "Last flew" TEXT, "Flying hours" FLOAT, "Location" TEXT)

what is the registration located on 31 january 1975 where first flew?
SELECT "Registration" FROM table_23456 WHERE "First flew" = '31 January 1975'
SELECT "Registration" FROM "table_23456" WHERE "First flew" = '31 January 1975'