Who was the vacator for the district of Nebraska at-large?
CREATE TABLE table_3012 (
    "District" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date successor seated" text
)
SELECT "Vacator" FROM table_3012 WHERE "District" = 'Nebraska At-large'
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: Who was the vacator for the district of Nebraska at-large? ### Input: CREATE TABLE table_3012 (
    "District" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date successor seated" text
) ### Response: SELECT "Vacator" FROM table_3012 WHERE "District" = 'Nebraska At-large'