Oracle Database Free

Both BOOLEAN data types and doing an INSERT with the VALUES clause (table values constructor) are new. The target table:

create table test_bool (id   number, tf   boolean);

This does not work:

insert into test_bool
  values
    (1,0),
    (2,'true');
ORA-01790: expression must have same datatype as corresponding expression

But doing the INSERTs one at a time does work:

insert into test_bool values (1,0);
insert into test_bool values (2,'true');

I can theorize what is happening from the error message: but in the case of INSERTs into BOOLEAN columns, both ‘true’ and 0 are valid values for the column. Is the order of operations wrong or are assumptions being made about the column, not knowing the datatype of the target column?