CREATE TABLE table_19310 ("Team" TEXT, "Average" TEXT, "Points" FLOAT, "Played" FLOAT, "1989-90" TEXT, "1990-91" TEXT, "1991-1992" FLOAT)

Name the least points where 1989-90 is 31
SELECT MIN("Points") FROM table_19310 WHERE "1989-90" = '31'
SELECT MIN("Points") FROM "table_19310" WHERE "1989-90" = '31'