CREATE TABLE table_2939 ("Season" FLOAT, "Lowest" FLOAT, "Low Team" TEXT, "Average" FLOAT, "Highest" FLOAT, "High Team" TEXT, "2nd Highest" FLOAT, "2nd Team" TEXT)

What was the season when the low team is chicago sting?
SELECT "Season" FROM table_2939 WHERE "Low Team" = 'Chicago Sting'
SELECT "Season" FROM "table_2939" WHERE "Low Team" = 'Chicago Sting'