Option 1 states that the executive power of the Union is vested in the President. This statement is correct. As per Article 53 of the Indian Constitution, the executive power of the Union is vested in the President and is exercised by him either directly or through officers subordinate to him.

Option 2 states that the executive power is exercised by the President only through officers subordinate to him. This statement is incorrect. While it is true that the President can exercise his executive power through officers subordinate to him, he can also exercise it directly without the involvement of any officers.

Option 3 states that the supreme command of the defence forces of the Union is vested in the President. This statement is correct. As per Article 53 of the Indian Constitution, the President is the Supreme Commander of the defence forces of the Union.

Therefore, the correct answer is option 3, which states that statements 1 and 3 are correct. Option 2 is incorrect as statement 2 is incorrect.