In Logstash v1.1.13, multiple matches in a grok filter would keep trying until it found a pattern that didn't have a grok parse failure. This does not seem to work as expected in 1.2.1. The first pattern works if it matches, but if it fails, the next pattern is not attempted.
In previous versions, the "hello" field would contain "1000" for the first input and "world" for the second input. I know you're supposed to grep things before you grok, but this feature still shouldn't have disappeared without warning.
This still works. It's just that your second pattern does not match. I replaced "DATA" with "GREEDYDATA" in your config and then it works:
Support done by Bernd