Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Date | Tournament | Surface | Partnering | Opponent in the final | Score |
| --- | --- | --- | --- | --- | --- |
| August 16, 2004 | Washington, D.C. , United States | Hard | Dmitry Tursunov | Chris Haggard Robbie Koenig | 7–6 3 , 6–1 |
| July 4, 2005 | Newport , U.S. | Grass | Graydon Oliver | Jordan Kerr Jim Thomas | 7–6 5 , 7–6 5 |
| April 14, 2008 | Valencia , Spain | Clay | Filip Polášek | Máximo González Juan Mónaco | 7–5, 7–5 |
| August 4, 2008 | Los Angeles , U.S. | Hard | Dušan Vemić | Rohan Bopanna Eric Butorac | 7–6 5 , 7–6 5 |
| February 22, 2009 | Memphis, Tennessee , U.S. | Hard | Filip Polášek | Mardy Fish Mark Knowles | 7–6 7 , 6–1 |
| June 19, 2009 | Eastbourne , United Kingdom | Grass | Filip Polášek | Mariusz Fyrstenberg Marcin Matkowski | 6–4, 6–4 |
Question:
Name the Surface that of Tournament of valencia , spain?
Answer:
Clay