What is the win % of the 2003 atp world tour finals?
CREATE TABLE "grand_slam_timeline" (
  "tournament" text,
  "2003" text,
  "2004" text,
  "2005" text,
  "2006" text,
  "2007" text,
  "2008" text,
  "2009" text,
  "2010" text,
  "2011" text,
  "2012" text,
  "win_pct" text
);
SELECT "win_pct" FROM "grand_slam_timeline" WHERE "2003"='atp world tour finals';