Task: Question Generation
Input (English): Confederates held East Tennessee despite the strength of Unionist sentiment there, with the exception of extremely pro-Confederate Sullivan County. The Confederates, led by General James Longstreet, did attack General Burnside's Fort Sanders at Knoxville and lost. It was a big blow to East Tennessee Confederate momentum, but Longstreet won the Battle of Bean's Station a few weeks later. The Confederates besieged Chattanooga during the Chattanooga Campaign in early fall 1863, but were driven off by Grant in November. Many of the Confederate defeats can be attributed to the poor strategic vision of General Braxton Bragg, who led the Army of Tennessee from Perryville, Kentucky to another Confederate defeat at Chattanooga.
Output (English): Which Union general broke the Confederate siege of Chattanooga in November 1863?