CREATE TABLE table_17237 ("Tournament" CLOB, "Date" CLOB, "City" CLOB, "Country" CLOB, "Surface" CLOB, "Singles champions" CLOB, "Doubles champions" CLOB)

How many doubles champions were there for the Serbia f6 Futures tournament?
SELECT COUNT("Doubles champions") FROM table_17237 WHERE "Tournament" = 'Serbia F6 Futures'
SELECT COUNT("Doubles champions") FROM "table_17237" WHERE "Tournament" = 'Serbia F6 Futures'