how long did sala burton serve ?
CREATE TABLE table_204_145 (
    id number,
    "representative" text,
    "state" text,
    "district(s)" text,
    "served" text,
    "party" text,
    "date of birth" text,
    "date of death" text,
    "age" text
)
SELECT "served" - "served" FROM table_204_145 WHERE "representative" = 'sala burton'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: how long did sala burton serve ? ### Input: CREATE TABLE table_204_145 (
    id number,
    "representative" text,
    "state" text,
    "district(s)" text,
    "served" text,
    "party" text,
    "date of birth" text,
    "date of death" text,
    "age" text
) ### Response: SELECT "served" - "served" FROM table_204_145 WHERE "representative" = 'sala burton'