Mr.Harsh
Please verify your Tax Credit Statement (Form No.26AS) whether you have got the credit for the TDS for the concerned year. If you do not get credit for the TDS in your Tax Credit Statement (Form No.26AS), you will not get credit for the same as prepaid taxes while processing your return of income u/s 143(1) of Income-tax Act, 1961. For this reason a demand arose in your intimation u/s 143(1) which is considered itself as a demand notice u/s 156 aslo.
The reasons for not getting credit for the TDS in your Tax Credit Statement (Form No.26AS) may be that the person who has deducted tax at source from the payment made to you,
(i) did not deposit the deducted tax to the credit of cental governemnt
or
(ii) did not file TDS returns as required u/s 206
or
(iii) there might be some mistakes in the TDS return filed by the deductor which were not rectified
Hence
(i) you have to verify your Tax Credit Statement (Form No.26AS), if TDS is given credit in the Tax Credit Statement you can move an application u/s 154 requesting the Assessing Officer to give due credit for the TDS.
(ii) if no credit is given for the TDS in the Tax Credit Statement, contact the person who deducted tax at source from the payment made to you
and
(iii) inform the fact to the Assessing Officer and request him to keep the demand in abeyance till the TDS is given credit in your Tax Credit Statement.
Best Wishes
Sathikonda