Using OR in GraphQl search query

I’m trying to search queries for different github-topics.
The idea is to fetch all repositories with the following topic logic:

(substrate OR polkadot) AND blockchain

The AND is easy, you just list all topics, but is there a way to do OR? Do I need separate queries for that?

search(query: "topic:substrate topic:polkadot", type: REPOSITORY, last: 100){...}

thanks