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 | Both | Daytona International Speedway | February 1 February 2 |
| Superflo 12 Hours of Sebring | 12 Hours | Both | Sebring International Raceway | March 15 |
| NAPA Grand Prix of Atlanta | 2 Hours | GTS | Road Atlanta | April 19 |
| NAPA Grand Prix of Atlanta | 2 Hours | WSC | Road Atlanta | April 20 |
| Dodge Dealers Grand Prix | 1 Hour 45 Minutes | GTS | Lime Rock Park | May 26 |
| Dodge Dealers Grand Prix | 1 Hour 45 Minutes | WSC | Lime Rock Park | May 26 |
| First Union Six Hours at the Glen | 6 Hours | Both | Watkins Glen International | June 1 |
| California Grand Prix | 1 Hour 45 Minutes | GTS | Sears Point Raceway | July 13 |
| California Grand Prix | 2 Hours | WSC | Sears Point Raceway | July 13 |
| Mosport Festival | 1 Hour 45 Minutes | GTS | Mosport International Raceway | August 31 |
| Mosport Festival | 2 Hours | WSC | Mosport International Raceway | August 31 |
| Sportscar Grand Prix | 1 Hour 45 Minutes | GTS | Las Vegas Motor Speedway | September 20 |
| Sportscar Grand Prix | 2 Hours | WSC | Las Vegas Motor Speedway | September 20 |
| Festival of Road Racing | 2 Hours | WSC | Pikes Peak International Raceway | September 28 |
| Festival of Road Racing | 1 Hour 45 Minutes | GTS | Pikes Peak International Raceway | September 28 |
| NAPA Sebring Octoberfest | 2 Hours | WSC | Sebring International Raceway | October 18 |
| NAPA Sebring Octoberfest | 1 Hour 45 Minutes | GTS | Sebring International Raceway | October 18 |
| VISA Sports Car Championship | 1 Hour 45 Minutes | GTS | Laguna Seca Raceway | October 26 |
| VISA Sports Car Championship | 1 Hour 45 Minutes | WSC | Laguna Seca Raceway | October 26 |
Question:
What circuit was on June 1 with a class of both?
Answer:
Watkins Glen International