How to represent the SQL value NULL in ActiveRecord#create calls?

Since seeds.rb is in Ruby, I'm guessing that if I want the effect of

insert into foo values (hoo: "ioo", koo: null);

I should do something like

Foo.create(hoo: "ioo", koo: nil)

Does the Ruby value nil map to the SQL value null in this case? I'm aware that

Foo.create(hoo: "ioo")

will create a row with koo of NULL, but the lines of my seeds.rb in this case are strings concatenated together in a quick-n-dirty SQL query, so simply skipping columns with null values might require even more mental effort than getting the node module better-sqlite3 to stop spitting out version mismatch messages. I suppose I could rake these seeds and test out my nil->NULL hypothesis instead of asking here, but I'm new enough to rails that I'm paranoid about breaking things.