CREATE TABLE table_37850 ("Position" FLOAT, "Team" TEXT, "Points" FLOAT, "Played" FLOAT, "Drawn" FLOAT, "Lost" FLOAT, "Against" FLOAT, "Difference" TEXT)

Difference of - 20, and a Position smaller than 17 is the highest against?
SELECT MAX("Against") FROM table_37850 WHERE "Difference" = '- 20' AND "Position" < '17'
SELECT MAX("Against") FROM "table_37850" WHERE "Difference" = '- 20' AND "Position" < '17'