user: Question: What is the fastest lap of the Oschersleben circuit with Audi Sport Team Abt as the winning team?
Columns: ['Circuit', 'Date', 'Pole position', 'Fastest Lap', 'Winning driver', 'Winning team', 'Winning manufacturer']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Präsentation Düsseldorf', '6 April', 'no race', 'no race', 'no race', 'no race', 'no race']
SQL:

assistant: SELECT "Fastest Lap" FROM "Table" WHERE "Winning team" = 'Audi Sport Team Abt' AND "Circuit" = 'Oschersleben';