If you defeated Groudon instead of catching it, depending on the game, you'll either have lost it for good or you'll be able to catch it again after defeating the Elite 4.
There are a number of reasons why Groudon might be missing. You could be in the wrong place, or it has already been caught, or it was defeated.
you can't
Once you have defeated Gordor and have captured Kyogre and Groudon, you will find Raquaza at the place that you defeated Gordor.
Neither. They are both Masters of their element (Fire/Water). The level of their power depends soley upon which has been better trained. I've defeated Groudon with Kyogre and Kyogre with Groudon so I know from experience...
First off you need to defeat the elite four, then you get sent home. Go to the Weather Institute, and then he well tell you were Groudon is hiding.
You must first wait until you are level 40 and have defeated Rayquaza. You then must battle him until he befreinds you.
If you are talking about when you get defeated in a dungeon, in special dungeons the system will ask if you want to send out a rescue statement. (i.e., being defeated in dungeons where you are on a special mission like defeating Groudon or Dusknoir.)
In Pokemon SoulSilver, you can only get Groudon. If you want a Kyogre, trade with someone, use a cheat, whatever. To get a Groudon, go to Route 47, and look around for the Embedded Tower. Inside is a Groudon, but it will only appear there once you have defeated Red and obtained the Red Orb from Mr. Pokemon. Also, if you have a Kyogre and Groudon in your party when you talk to Prof. Oak, he will tell you a story and then Rayquaza will appear in the Embedded Tower! Hope I helped ;)
Groudon is AWESOME!
There is no ruby in groudon.
groudon is better
groudon