user: Question: Name the replaced by where date of vacancy is 31 December 2008 where position in table is 1st
Columns: ['Team', 'Outgoing manager', 'Manner of departure', 'Date of vacancy', 'Replaced by', 'Date of appointment', 'Position in table']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['AaB', 'Erik Hamrén', 'End of contract', '30 June 2008', 'Bruce Rioch', '1 July 2008', 'Pre-season']
SQL:

assistant: SELECT "Replaced by" FROM "Table" WHERE "Date of vacancy" = '31 December 2008' AND "Position in table" = '1st';