Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Round | Circuit | Date | Length | Pole Position | GT3 Winner | GT4 Winner |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Oulton Park | 25 April | 60 mins | No. 5 Scuderia Vittoria | No. 1 Trackspeed | No. 44 ABG Motorsport |
| 1.0 | Oulton Park | 25 April | 60 mins | Charles Bateman Michael Lyons | David Ashburn Richard Westbrook | Peter Belshaw Marcus Clutton |
| 2.0 | Oulton Park | 25 April | 60 mins | No. 1 Trackspeed | No. 5 Scuderia Vittoria | No. 42 Century Motorsport |
| 2.0 | Oulton Park | 25 April | 60 mins | David Ashburn Richard Westbrook | Charles Bateman Michael Lyons | Jake Rattenbury Josh Wakefield |
| 3.0 | Snetterton 300 | 15 May | 120 mins | No. 10 CRS Racing | No. 23 United Autosports | No. 44 ABG Motorsport |
| 3.0 | Snetterton 300 | 15 May | 120 mins | Glynn Geddie Jim Geddie | Matt Bell Michael Guasch | Peter Belshaw Marcus Clutton |
| 4.0 | Brands Hatch | 19 June | 120 mins | No. 21 MTech | No. 2 Trackspeed | No. 44 ABG Motorsport |
| 4.0 | Brands Hatch | 19 June | 120 mins | Duncan Cameron Matt Griffin | Tim Bridgman Gregor Fisken | Peter Belshaw Marcus Clutton |
| 5.0 | Spa-Francorchamps | 9 July | 60 mins | No. 59 McLaren GT | No. 1 Trackspeed | No. 50 Scuderia Vittoria |
| 5.0 | Spa-Francorchamps | 9 July | 60 mins | Chris Goodwin Andrew Kirkaldy | David Ashburn Richard Westbrook | Dan Denis David McDonald |
| 6.0 | Spa-Francorchamps | 9 July | 60 mins | No. 1 Trackspeed | No. 21 MTech | No. 48 Lotus Sport UK |
| 6.0 | Spa-Francorchamps | 9 July | 60 mins | David Ashburn Richard Westbrook | Duncan Cameron Matt Griffin | Phil Glew Ollie Jackson |
| 7.0 | Rockingham | 4 September | 60 mins | No. 23 United Autosports | No. 7 Beechdean Motorsport | No. 50 Scuderia Vittoria |
| 7.0 | Rockingham | 4 September | 60 mins | Matt Bell Michael Guasch | Jonathan Adam Andrew Howard | Dan Denis David McDonald |
| 8.0 | Rockingham | 4 September | 60 mins | No. 2 Trackspeed | No. 11 CRS Racing | No. 50 Scuderia Vittoria |
| 8.0 | Rockingham | 4 September | 60 mins | Tim Bridgman Gregor Fisken | Alex Mortimer Andrew Tate | Dan Denis David McDonald |
| 9.0 | Donington Park | 25 September | 180 mins | No. 1 Trackspeed | No. 5 Scuderia Vittoria | No. 48 Lotus Sport UK |
| 9.0 | Donington Park | 25 September | 180 mins | David Ashburn Stephen Jelley | Charles Bateman Michael Lyons | Phil Glew James Nash |
| 10.0 | Silverstone Arena | 8 October | 120 mins | No. 7 Beechdean Motorsport | No. 7 Beechdean Motorsport | No. 48 Lotus Sport UK |
Question:
When  david ashburn richard westbrook is the gt3 winner and 1 is the round what is the length?
Answer:
60 mins