user: Question: Which Reason is given when 1103 is the date for Became heir?
Columns: ['Heir', 'Status', 'Relationship to Monarch', 'Became heir', 'Reason', 'Ceased to be heir', 'Monarch']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Robert Curthose', 'Heir presumptive', 'Son', '1066', 'father became king', '1077', 'William I']
SQL:

assistant: SELECT "Reason" FROM "Table" WHERE "Became heir" = '1103';