My iPhone correctly says “Ottawa, Ontario, Canada”, while Google’s library doesn’t return the city?

There was a time when a phone number's area code and exchange would indicate a pretty constrained geographic area -- for a land-line. I don't think it's possible to do this kind of "find the geography from a phone number alone" lookup accurately in the modern environment. Whatever API Apple provided got your example number right, sure. But how will you know when it gets one wrong? How can you know how often it gets it wrong? What does it really mean to assign a place to a cell number?

My own phone number consistently gets pegged by these things as "belonging to" a specific town several miles away from where I live, probably because the exchange part of my number is one that used to be associated with that town. But that observation doesn't produce any kind of useful information today, it's just misleading.

https://en.wikipedia.org/wiki/Area_codes_613,_343,_and_753

The city info is there in the 613 block, so Google just ignores it.

The first 3 digits, i.e. the ones between the parentheses in your example, is called the area code.

Area codes in North America were divvied up by US and Canada, and they share the same phone number structure.

Older area codes tend to have a "1" or "0" in the middle, but that convention went away, as devices like fax machines(!) and mobile phones proliferated, and more numbers were needed to handle the load.

The various telephone companies coordinate through the North American Numbering Plan (NANP)

A list of area codes and where they're supposed to be assigned to: https://en.wikipedia.org/wiki/List_of_North_American_Numbering_Plan_area_codes

I say "supposed" because you can take a mobile phone number anywhere these days.

The 2nd 3 digits, e.g. "745" in your example, traditionally meant a certain area within the area code. So for example, phone numbers in the 613 area code having 2nd 3 digits of "743", "744" and "745" would typically be to addresses near each other.

That might designate a specific city, or a group of towns.

Once again, mobile phones have taken some of that meaning away as landlines are disappearing.

I think that relying upon a closed source source of data is perhaps not the right way to go about this. Assuming that they are a source of truth to begin with is problematic.

The area code. In this case 613. There's enough of them to correlate with a single area.