Oracle - Me aparece ORA-00917: coma faltante

CREATE TABLE tabla1
person_id NUMBER,
first_name VARCHAR(5) NOT NULL,
PRIMARY KEY (person_id)
);


ALTER TABLE tabla1
add last_name VARCHAR(50);

ALTER TABLE tabla1
MODIFY last_name NOT NULL;

AlTER TABLE tabla1
MODIFY first_name VARCHAR(50);

INSERT INTO tabla1(person_id, first_name, last_name)
VALUES (1,'Ross', 'Allan');

select * from tabla1;

ALTER TABLE tabla1
add matricula NUMBER;

ALTER TABLE tabla1
MODIFY matricula NUMBER DEFAULT 0;

ALTER TABLE tabla1
add DIRECCION VARCHAR(50) DEFAULT 'ABC';

ALTER TABLE tabla1
DROP COLUMN matricula;

ALTER TABLE tabla1 RENAME COLUMN direccion to direcciones ;

SELECT first_name FROM tabla1;

UPDATE tabla1 SET first_name = 'allan';

INSERT INTO tabla1 (person_id, first name, last name, direcciones) values (2, 'lopez','derec', 'doctores');
INSERT INTO tabla1 (person_id, first name, last name, direcciones) values (3, 'sanchez','carlos', 'buenos aires');
INSERT INTO tabla1 (person_id, first name, last name, direcciones) values (4, 'lopez','derec', 'doctores');
INSERT INTO tabla1 (person_id, first name, last name, direcciones) values (5, 'nitales','alex', 'roma');
INSERT INTO tabla1 (person_id, first name, last name, direcciones) values (6, 'pulido','miguel', 'obrera');