user: Question: Who wrote the episodes directed by David Straiton?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [89.0, 1.0, '"A Witch\'s Tail (Part 1)"', 'James L. Conway', 'Daniel Cerone', 'September22,2002', 4301089.0, '6.3']
SQL:

assistant: SELECT "Written by" FROM "Table" WHERE "Directed by" = 'David Straiton';