On what date is the winning team Abt Sportsline and pole position Mattias Ekström in the Circuit Ricardo Tormo , Valencia?
CREATE TABLE "race_calendar_and_results" (
  "round" text,
  "circuit" text,
  "date" text,
  "pole_position" text,
  "fastest_lap" text,
  "winning_driver" text,
  "winning_team" text
);
SELECT "date" FROM "race_calendar_and_results" WHERE "winning_team"='Abt Sportsline' AND "pole_position"='Mattias Ekström' AND "circuit"='Circuit Ricardo Tormo , Valencia';