With reference to Indian history, consider the following statements :

1. The first Mongol invasion of India happened during the reign of Jalal-ud-din Khalji.

2. During the reign of Ala-ud-din Khalji, one Mongol assault marched up to Delhi and besieged the city.

3. Muhammad-bin-Tughlaq temporarily lost portions of north-west of his kingdom to Mongols.

Which of the statements given above is/are correct ?