If you can show the actual connectors involved, it will make it easier to help you find connectors you can use to make a cable to connect them.
The results I get for C13 are for an AC cord to the wall; that is normally only on the charger-to-wall side.
View attachment 349031
I've seen it misused on the DC side of charger-to-battery connections, where it could lead to a fire (because people will fail to understand a charger is required between it and the wall, and find a cable that will connect that directly to the wall).
The most likely thing you will end up doing is taking a mating cable for that connection, such as an extension cable like this, cutting it in half, and using just the half you need, along with a cable (perhaps another extension) for the middrive side connector type, and splice the wires together at the cut ends with the correct polarity that you will determine with a multimeter.
View attachment 349032
Is this the only connector on your battery?
Which pins on it have what voltages, relative to the battery negative, as tested with your multimeter or voltmeter?
Also, Is the battery the correct voltage range for your middrive, *and* can it supply the required current (amps) to the mid drive under worst case highest load? (there are multiple Tongsheng mid drive models and versions, so we don't know which one you have, and we have no information on your battery at all).