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:
| Race | Length | Class | Circuit | Date |
| --- | --- | --- | --- | --- |
| Rolex 24 at Daytona | 24 Hours | All | Daytona International Speedway | February 5 February 6 |
| Contac 12 Hours of Sebring | 12 Hours | All | Sebring International Raceway | March 19 |
| Grand Prix of Atlanta | 1 Hour | GT | Road Atlanta | April 17 |
| Grand Prix of Atlanta | 2 Hours | WSC | Road Atlanta | April 17 |
| The New England Dodge Dealers Grand Prix | 1 Hour | GT | Lime Rock Park | May 30 |
| The New England Dodge Dealers Grand Prix | 2 Hours | WSC | Lime Rock Park | May 30 |
| The Glen Continental | 3 Hours | All | Watkins Glen International | June 26 |
| Indy Grand Prix | 1 Hour | GT | Indianapolis Raceway Park | July 10 |
| Indy Grand Prix | 2 Hours | WSC | Indianapolis Raceway Park | July 10 |
| Monterey Sports Car Grand Prix | 1 Hour | GT | Laguna Seca Raceway | July 24 |
| Monterey Sports Car Grand Prix | 2 Hours | WSC | Laguna Seca Raceway | July 24 |
| Grand Prix of Portland | 1 Hour | GT | Portland International Raceway | August 7 |
| Grand Prix of Portland | 2 Hours | WSC | Portland International Raceway | August 7 |
| Exxon World Sports Car Championships | 1 Hour | GT | Phoenix International Raceway | October 1 |
| Exxon World Sports Car Championships | 2 Hours | WSC | Phoenix International Raceway | October 1 |
Question:
What was the length for GT class at Portland International Raceway?
Answer:
1 Hour