Yusuf, you should know by now that the best power supply would be the power supply that can easily meet the demands of the pump motor as well as your circuit. That includes any surge current the pump motor may draw on start. Additionally when a motor starts and draws an inrush current it can cause the bus voltage to drop from the PSU, that sudden drop can wreak havoc with your CMOS. In most cases it is unwise to run a pump motor and CMOS circuits off the same power source. Since you do not post any current specifications there is no way to answer your question. However, I will tell you that I would never consider using a pair of 6 volt Nokia (or any other) mobile charger units in series as a power supply or source for a project involving a pump motor and CMOS circuits. Take it for what it is worth.
Just My Take
Ron