Easy t-SQL (need help)

Hi Gurus,

colm01    Colum02    colum03      colum04      colum05

10001    America      World 		10 	null

10002   Virginia	Europe   	20 	10

10003   Florida 	Asia   	      30 	10

In this table, I want to have a new column (colum06), that gives me NULL for America and 10001 for Virginia and Florida

Thanks in advance

ebro