That’s not how system prompts work. You’re simply asking it to role-play a user-assistant chat where the user tries to circumvent the system prompt and asks who the assistant is. Unsurprisingly, the majority of such chat scripts on the web will have been created with ChatGPT. Hence the answer you are seeing.
This is clearly what is happening. Deepseek can train on o1 generated synthetic data and generate a very capable and small model. This requires that somebody build an o1 and make it available via API first.