1023456789
1234567
1,234,567
102
103
102
1023456789
1234567
102345
Since there are only five different digits, a 6-digit number can only be generated if a digit can be repeated. If digits can be repeated, the smallest 6-digit number is 111111.
0123456789
10234567
1,234,567
102
103
100,000,000,000
102345 is the smallest [positive] 6-digit number with no repeats.