By making entry in wrong column you have not caused revenue loss to the department. Since the demand SCN has been issued, you have to file reply to the SCN with supporting documents i.e. books of accounts. Books of accounts are statutory docs. If your books of accounts are correct and there is no difference in the books of accounts, then there is nothing to worry. You are to justify correctness and genuineness in the books of account regarding availment of ITC.
After the issuance of demand show cause notice, rectification will be possible only after the demand SCN is adjudicated. So wait for the Adjudication Order.