Show theme and year for all exhibitions in an descending order of ticket price.
SELECT theme ,  YEAR FROM exhibition ORDER BY ticket_price DESC
SELECT theme ,  YEAR FROM exhibition ORDER BY ticket_price DESC
[{'Theme': 'Spring', 'Year': 2008}, {'Theme': 'Santa Claus', 'Year': 2004}, {'Theme': 'Christmas stocking', 'Year': 2005}, {'Theme': 'Christmas Tree', 'Year': 2007}, {'Theme': 'Santa Claus and Rudolph the Red-Nosed Reindeer', 'Year': 2006}, {'Theme': 'Summer', 'Year': 2009}]