user: Question: What episode was the last appearance of the character, Rikki Sandoval?
Columns: ['Character', 'Portrayed by', 'Relationship', 'First appearance', 'Last appearance']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Reed Garrett', 'Kyle Gallner', "Son of Mac Taylor's late wife", '"Consequences"', '"Pot of Gold"']
SQL:

assistant: SELECT "Last appearance" FROM "Table" WHERE "Character" = 'Rikki Sandoval';