user: Question: Which series were played on April 18?
Columns: ['Game', 'Date', 'Team', 'Score', 'High points', 'High rebounds', 'High assists', 'Location Attendance', 'Series']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'April 18', 'Los Angeles Lakers', 'L 79–87 (OT)', 'Kevin Durant (24)', 'Nick Collison (8)', 'Russell Westbrook (8)', 'Staples Center 18,997', '0-1']
SQL:

assistant: SELECT "Series" FROM "Table" WHERE "Date" = 'April 18';