Table:
text: 2008 French Road Cycling Cup
Events
Events
Date_ Event Winner Team Series_leader
April 19 Tour du Finistère David Lelay ( FRA ) Bretagne-Armor Lux Jimmy Casper ( FRA )
April 20 Tro-Bro Léon Frédéric Guesdon ( FRA ) Française des Jeux Jimmy Casper ( FRA )
May 4 Trophée des Grimpeurs David Lelay ( FRA ) Bretagne-Armor Lux David Lelay ( FRA )
May 31 Grand Prix de Plumelec-Morbihan Thomas Voeckler ( FRA ) Bouygues Télécom David Lelay ( FRA )
August 3 Polynormande Arnaud Gérard ( FRA ) Française des Jeux Jérôme Pineau ( FRA )
August 31 Châteauroux Classic Anthony Ravard ( FRA ) Agritubel Jérôme Pineau ( FRA )
September 21 Grand Prix d`Isbergues William Bonnet ( FRA ) Crédit Agricole Jérôme Pineau ( FRA )

Question: The 2008 French Road Cycling Cup, what is the series leader with a date that is May 31st?