create or replace function find_object_level(obj_x VARCHAR2)
RETURN number as lvl_object number;
begin
    SELECT level
    into lvl_object
    from objects
    where name = obj_x
    START WITH  parent_id is null
    CONNECT BY PRIOR object_id = parent_id;

    return lvl_object;
end;

select find_object_level(name) from objects where name = 'Томас Шелби'