SELECT NULL returns a type mismatch with DuckDB

[ankrgyl]

qs> select null;
<repl>: error: Runtime error: SQL Engine returned a record batch with an invalid schema: expected List(Record([Field { name: "NULL", type_: Atom(Null), nullable: true }])), got List(Record([Field { name: "NULL", type_: Atom(Int32), nullable: true }])). This can happen if the type is declared incorrectly or if there's a bug in the engine.
qs>

It seems like DuckDB defaults its (Arrow) value to be an int32. We should probably do the same, just for compatability's sake.