How will you handle a call if the person calling is seeking for a job placement?

Just ask that person to send his/her resume with a formal letter of application for employment.

First of all you should ask them how they got your number? as maybe someone can be playing a prank on you. If you know or he got your number from someone known then you should just give the number of HR dept. If the caller is a friend then tell him , you will see if there is any job available in your company and email his resume aswell.

Are you the personnel director? If so then it should be easy, if not then direct them to the proper person to handle it.