user: Question: Who is the written by when Mark Worthington is the director?
Columns: ['Series #', 'Season #', 'Episode title', 'Written by', 'Directed by', 'U.S. viewers (millions)', 'Original air date']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: [66.0, 1.0, '" The Butterfly Effect (Part 1) "', 'Sheila Lawrence & Henry Alonso Myers', 'John Terlesky', '5.01', 'October16,2009']
SQL:

assistant: SELECT "Written by" FROM "Table" WHERE "Directed by" = 'Mark Worthington';