Dear Amir,
The liability to deduct TDS accrues with contract B. The point to be noted here is you deduct TDS for both amounts of contract A & B but the date of deduction will be the date of credit of contract B. Hence the total TDS to be deducted on 01.11.2009 for Rs 34,000 (15,000 + 19, 000). The due date of payment will be 7.12.2009.
Hope this helps.
Sahana Murthy.