user: Question: What was the date of vacancy after the outgoing manager, Ralf Santelli departed?
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: ['VfL Osnabrück', 'Claus-Dieter Wollitz', 'FC Energie Cottbus purchased rights', '30 June 2009', 'Karsten Baumann', '1 July 2009', 'Pre-Season']
SQL:

assistant: SELECT "Date of vacancy" FROM "Table" WHERE "Outgoing manager" = 'Ralf Santelli';