Finding assessing officer

Hi,

I as an Individual filed return for AY 2012-13 with challan for self assessment tax. I got notice that I haven't deposited the amount I have mentioned as self assessment tax. Reason for notification was because Challan was generated for AY 2011-12.

As per my knowledge now this information can be corrected only by Assessing officer, but I have confusion regarding who will be Assessing officer based on following information:

ITR filed online.

Jurisdiction Assessing officer as per PAN details: Pune

Assessing officer as per address mentioned in ITR: Amritsar

Whom should I approach for getting this corrected?

Thanks,

Harvinder