Validation Sellphone Laravel

One possible solution would to use regex.

'phone' => 'required|regex:/(01)[0-9]{9}/'
This will check the input starts with 01 and is followed by 9 numbers. By using regex 
you dont need the numeric or size validation rules.

If you want to reuse this validation method else where, it would be a good idea to 
create your own validation rule for validating phone numbers.

Docs: Custom Validation - https://laravel.com/docs/5.4/validation#custom-validation-rules

In your AppServiceProviders boot method:

Validator::extend('phone_number', function($attribute, $value, $parameters)
{
    return substr($value, 0, 2) == '01';
});
This will allow you to use the phone_number validation rule anywhere in your application, 
so your form validation could be:

'phone' => 'required|numeric|phone_number|size:11'
In your validator extension you could also check if the $value is numeric and 11 
characters long.
Wide-eyed Wolf