Sarah Perez, TechCrunch:

With the added Siri integration, you’ll be able to ask the assistant both informational queries, plus those requiring real-time information.

For example, you may ask Siri something like “When are the California primaries?,” which is a more straightforward question, or “Who’s winning the New Hampshire primaries?,” which requires updated information.

On my iPhone, most everything worked as advertised. On HomePod, some questions got the, “I can’t get the answer to that on HomePod” response.

Try it yourself:

What were the results of the Democratic Iowa Caucus?

This comes up when the information has not been pre-parsed for HomePod Siri and requires a web lookup.