CREATE TABLE table_39090 ("Election" FLOAT, "Labour" FLOAT, "Conservative" FLOAT, "Liberal" FLOAT, "Social Democratic Party" FLOAT, "Social and Liberal Democrats/ Liberal Democrats" FLOAT, "Independent" FLOAT, "Green" FLOAT, "Other" TEXT, "Control" TEXT)

Which Social Democratic Party has a Green smaller than 0?
SELECT AVG("Social Democratic Party") FROM table_39090 WHERE "Green" < '0'
SELECT AVG("Social Democratic Party") FROM "table_39090" WHERE "Green" < '0'