Datetime comparacion entre fechas

[alexizdiamondz]

Buenas a todos en el foro, soy un nuevo miembro estudiante novato de tics.
Tengo una duda acerca de como hacer la siguiente instrucción proporcionada por mi profesor, de BD la cual es la siguiente: ¿Que pedido fue el que ha demorado mas desde que se realizo el pedido?

Esta es mi tabla:

Código MySQL:

create table orders(
order_id int primary key,
customer_id int,
taken_by_employee_id int,
deliveried_by_employee_id int,
delivery_status_code int,
vehicle_id int,
datetime_order_taken datetime,
detetime_order_deliveried datetime,
total_order_price varchar(6),
other_order_details varchar(100)
);
 

y estos son mis datos insertados:

Código MySQL:

insert into orders values(2387,36595,365,365,63589,2354,'2010-02-15 10:50:34','2010-02-15 12:30:34','3719','orden correcta');
insert into orders values(5686,13468,155,155,97462,6589,'2010-04-13 09:20:12','2010-04-13 11:25:35','3652','orden correcta');
insert into orders values(1358,13645,125,125,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
insert into orders values(2358,32659,584,584,19623,2154,'2010-12-06 02:13:53','2010-12-06 04:58:32','359','orden correcta');
insert into orders values(4568,23565,895,895,91587,3164,'2010-10-03 01:56:32','2010-10-03 03:31:24','369','orden correcta');
insert into orders values(2345,23565,895,895,91587,3164,'2010-10-03 01:56:32','2010-10-03 03:31:24','369','orden correcta');
insert into orders values(8753,23565,895,895,91587,3164,'2010-10-03 01:56:32','2010-10-03 03:31:24','369','orden correcta');
insert into orders values(1538,13645,125,125,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
insert into orders values(1552,13645,365,825,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
insert into orders values(1599,13645,584,365,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
insert into orders values(5253,13645,125,365,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
insert into orders values(1338,13645,584,125,31468,8754,'2010-08-05 12:25:15','2010-08-05 02:32:45','254','orden cancelada');
 

Alguien que me pueda ayudar?
Se lo agradecería demasiado.