What is the logic behind the sequence of numbers **********?

Question

Find the logic behind the numbers and then find the value of the missing number.

Answer 1

nonrepeating unambiguous number: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Answer 2

If you add the leading 8, it becomes **********,
the only number that has all the (decimal) digits arranged in alphabetical order (in English).