user: Question: What is the name of the first appearance when Chad Williams is a portrayal?
Columns: ['Character', 'Portrayed by', 'Crime', 'First appearance', 'Last appearance']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Sonny Sassone', 'Michael DeLuise', 'Murder (2 counts)', '"Tanglewood"', '"Run Silent, Run Deep"']
SQL:

assistant: SELECT "First appearance" FROM "Table" WHERE "Portrayed by" = 'Chad Williams';