Step 1: Identify the achievements of each athlete
Milkha Singh, also known as "The Flying Sikh", won the 400m gold medal at both the Asian Games (1958) and the Commonwealth Games (1958).
Step 2: Evaluate other options
Usain Bolt is a Jamaican athlete, not Indian.
Ram Singh is not known for such achievements.
P T Usha is a legendary Indian sprinter, but she never won gold in the Commonwealth Games.
Step 3: Conclude
Milkha Singh is the only correct choice based on achievements in both events.