Which 2008 Tournament has a 2007 of a and a 2010 of qf?
CREATE TABLE "singles" (
  "tournament" text,
  "1999" text,
  "2000" text,
  "2001" text,
  "2002" text,
  "2003" text,
  "2004" text,
  "2005" text,
  "2006" text,
  "2007" text,
  "2008" text,
  "2009" text,
  "2010" text,
  "2011" text
);
SELECT "2008" FROM "singles" WHERE "2007"='a' AND "2010"='qf';