Question: Which of these two pizzerias has had the same owners for longer, Regina Pizzeria or Pietro's Pizza?

Context paragraphs:
Rabbe Grönblom: Rabbe Anders Grönblom (May 3, 1950 Helsinki, Finland – June 29, 2015) was a Finland-Swedish businessman who started a successful pizza business in Vaasa, Finland.  His first company—a pizzeria—was called "O sole mio" and it was founded in 1976 in the center of Vaasa.  From there he expanded to a pizza franchise chain first called "Pizzeria N:o 1".  He was known as the "Pizza-emperor" (Pizzakeisari in Finnish), because he was the founder of a well known pizza franchise chain called Kotipizza which was the new name of "Pizzeria N:o 1" which expanded fast outside of Vaasa.  The chain is said to be the biggest one in the Nordic countries.  He was also the founder of a shipping company called RG Line, a hotel chain called Omenahotelli and another pizza chain called Golden Rax Pizzabuffet.  Most of his companies are subsidiaries of Grönblom International LTD, where Rabbe Grönblom acted as director.  Golden Rax Pizzabuffet however is nowadays a part of Finland's largest hotel & restaurant company Restel Oy Ltd, where Rabbe Grönblom sat on the board.  He was also on the board of the Finnish tyre company Nokian Renkaat (since 2003).

Pietro's Pizza: Pietro's Pizza is a small pizza chain in the U.S. state of Oregon.  Founded in 1957, the chain grew to about 80 restaurants and changed owners several times before shrinking to only four stores.  The company is based in Milwaukie, Oregon.

California-style pizza: California-style pizza (also known as California pizza or Gourmet pizza) is a style of single-serving pizza that combines New York and Italian thin crust with toppings from the California cuisine cooking style.  Its invention is generally attributed to chef Ed LaDou, and Chez Panisse, in Berkeley, California.  Wolfgang Puck, after meeting LaDou, popularized the style of pizza in the rest of the country.  It is served in a number of California Cuisine restaurants.  Such restaurant chains as California Pizza Kitchen, Extreme Pizza, and Sammy's Woodfired Pizza are three major pizza franchises associated with California-style pizza.  Nancy Silverton's Pizzeria Mozza is also a popular California-style pizza restaurant in Los Angeles.

Chicago Franchise Systems, Inc.: Chicago Franchise Systems, Inc. franchises operates Italian-based Chicago-style restaurants in Illinois, Georgia, California and Missouri which specialize in Chicago-style cuisine They have operated since 1990, when they took over the popular Nancy's Pizza chain of pizzerias.  Nancy's itself was started in 1971 by Nancy and Rocco Palese, a couple who claims to have invented the concept of stuffed pizza.  Today, there are 36 Nancy's locations in Chicago metropolitan area, as well as two location in the Atlanta, Georgia area, and one in the Los Angeles, CA area.  CFS, Inc. operates Al's Beef, a popular Italian beef restaurant that is extremely well known in downtown Chicago and is regarded as one of the best beef sandwiches in the country.  CFS, Inc. just launched Doughocracy Pizza + Brews, a fast casual pizza place that gives customers the "Freedom to Choose" their own toppings on a hand stretched pizza crust that can be paired with local craft beers.  There are two Doughocracy restaurants, one in Geneva, Illinois and one in University City, Missouri, a suburb of St. Louis.

Tutta Bella Neapolitan Pizzeria: Tutta Bella Neapolitan Pizzeria is an Italian restaurant chain with five locations in Washington State.  The first location was founded in 2004.  The restaurant specializes in "authentic" Neapolitan pizza and is certified by the non-profit Associaziona Verace Pizza Napoletana ("True Neapolitan Pizza Association") which certifies pizzerias that use traditional ingredients and processes.  Tutta Bella was the first restaurant in the Pacific Northwest to receive such certification.

Pizza Land: Pizza Land is an independently owned pizzeria located at 260 Belleville Turnpike in North Arlington, New Jersey, which featured in the opening credits of "The Sopranos".  Additionally, in "Law & Order" episode 10.6, "Marathon" (1999), a pizza box from the restaurant was used by a suspect to transport and conceal firearms.  The pizzeria was opened in 1965 by Italian immigrant Frank Di Piazza, who died in 1991.  The pizzeria was built by Pietro Di Piazza.  It was owned by Frank's son Tony Di Piazza .  Tony and Debra Hunkele always had the pizzeria packed but later on sold to pizza maker Al Pawlowicz until his death in 2010, who purchased the restaurant from DiPiazza's son.  The store is now owned by Eddie Twdroos.

Regina Pizzeria: Regina Pizzeria, also known as Pizzeria Regina, and originally called Regina Pizza, is a regional pizza chain in New England.  The company was founded in 1926 by Luigi D'Auria in Boston's North End neighborhood.  It has been run by the Polcari family since 1956.  The chain is a part of Boston Restaurant Associates and is headquartered in Lynnfield, Massachusetts.

Uno Pizzeria &amp; Grill: Uno Pizzeria & Grill (formerly Pizzeria Uno and Uno Chicago Grill), or more informally as Unos, is a franchised pizzeria restaurant chain under the parent company Uno Restaurant Holdings Corporation.  Uno Pizzeria and Grill is best known for its Chicago-style deep dish pizza.  Ike Sewell opened the first Pizzeria Uno in 1943.

Patsy's Pizzeria: Patsy's Pizzeria is a historic coal-oven pizzeria in New York City and is regarded as one of New York's original pizzerias as well as for its use of traditional New York style thin crust pizza.

Pizza Corner (Halifax): Pizza Corner is an intersection in Halifax, Nova Scotia, at the junction of Blowers Street and Grafton Street.  It is a local landmark originally consisting of three pizzerias: King of Donair, Sicilian Pizza and the European Food Shop.  Completing the four corners is the Presbyterian Church of Saint David, a provincially recognized heritage building.  All three pizzerias are known for their Halifax-style donairs, and the corner is a popular destination for hungry patrons of the local bars and pubs.

Supporting paragraphs: Regina Pizzeria Pietro's Pizza
Answer: Regina Pizzeria