How to prevent wrong inputs (only numbers) in Delphi?

How to prevent wrong inputs (only numbers) in Delphi?

I am trying to build a function/check to prevent wrong inputs from
keyboard and I am a little bit lost here.
function ReadInputs : integer;
var
number : integer;
begin
repeat
Write('Set random number (1-10): ');
Readln(number);
if NOT((number <= 10) AND (number >= 1)) then
begin
Writeln('Error! Type 1-10!');
end;
until (number >= 1) AND (number <= 10);
result := column;
end;
How to prevent from any other character to be input except numbers 1-10?
Why only numbers define in my function is not enough even when I set
integer? When I type for example "A" it crash, so what is the right way?
Thank you.