WASHINGTON - Seniors will face annual increases in premiums and deductibles — and a growing gap in coverage — for the prescription drugs they buy under the new Medicare law, budget analysts say. For example, the $250 annual deductible at the start of the program in 2006 is projected to rise to $445 by 2013. The legislation that won final congressional approval Tuesday would allow seniors to buy coverage — at an estimated monthly premium of $35 — for their prescription drugs beginning in three years. After they agreed to the monthly premiums and paid their first $250 in pharmacy...