user: Question: When Efrain Valdez was pitching, what was the highest home run?
Columns: ['Home Run', 'Game', 'Date', 'Inning', 'Location', 'Opposing Pitcher', 'Team']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 6.0, 'April 14', '6th', 'Tiger Stadium', 'Dave Johnson', 'Baltimore Orioles']
SQL:

assistant: SELECT MAX("Home Run") FROM "Table" WHERE "Opposing Pitcher" = 'Efrain Valdez';